Who were the most tragic / evil of the traitor Primarchs?

As I'm re-reading Angel Exterminatus at the moment, which contrasts two very different Primarchs, I got to thinking as to which of the traitor Primarchs were truly evil from the outset and which were victims of circumstance and character flaws. The Horus Heresy has fleshed most of these out to some extent making things a bit easier. There may be some spoilers in here so be warned. I will list them here in order of most innocent to most evil. Please feel free to comment or disagree. Cheers.

9. Magnus the Red - undoubtedly one of the good guys who was percsecuted by the Emperor for his continued use of his psychic abilites and ultimately 'killed' by Leman Russ for daring to disobey the edict of Nikea and bring ruin to the Emperors webway plans on Earth. Magnus was a pretty arrogant chap (wouldn't we all be with his powers?) but his actions stemmed from a desire to do good. First trying to better understand chaos, then attempting to save Horus from its clutches and finally trying to warn the Emperor of betrayal. Even when Russ arrives on Prospero and starts razing the city Magnus does not fight back initially. Only when his mortal body is broken and much of his legion dead does he finally begin his true descent into chaos, one that will ultimately lead to him siding with Horus as he approaches Terra. Definitely the most tragic of the Primarchs in my opinion.

8. Alpharius/Omegon - As the series has progressed it becomes clear that there are different agendas amongst the twins - one remaining true to the path of supporting Horus and the other seeking to aid the loyalist side. I found Legion to be one of the more interesting books so far and the choice the Primarchs were given by the Cabal an almost impossible one to rationalise. Basically, they were convinced to either side with the Emperor and let Chaos consume the human race as it did the Eldar before them, or to side with Horus and let Chaos burn itself out ultimately saving the Galaxy. Not the easiest of choices to make but ultimately they decide to act for the greater good and side with Horus. There is no malevolence towards the Emperor and it is simply a choice made to serve a covert agenda for the greater good of mankind. I think this was an interesting twist as it befits the duplicitous nature of the Alpha Legion so well. They are good guys playing bad guys and therefore they come second only to Magnus in this list.

7. Perturabo - I never knew much about Perturabo until I read Angel Exterminatus and thanks to Graham McNeill he has swiftly been elevated to the position of one of my favourites. He's effectively a misunderstood, underestimated chap, who is mostly regarded as a blunt tool to get the job done thanks to his prowess in battle and tactical brilliance. (which incidentally is portrayed as being second to none amongst his brothers) Beneath all of that is a conscientious person and someone who loves nothing more than to create rather than destroy. His love of design and his guilt over the fate of Olympia are testament to this. His legion was abused by the Emperor, being spread throughout the Galaxy and used to garrison worlds of conquest, while his brother Primarachs reaped the glory. This led to Perturabo siding with Horus, but he is far from sold on the idea of treachery. Indeed, he shows contempt for the behaviour of the Emperors Children,  respect for the Loyalist legions and laments for his lost relationship with his father and the oath of loyalty he has broken. Again, he appears a victim of circumstance, perhaps one whose hand was not as forced as Magnus, but far from the outright heretic some of the Primarchs can be claimed to be.

6. Lorgar - Although I must admit I was rooting for Corax to end the whiny little bitch by the end of The first Heretic, there are many tragic components to Lorgars story also. Ultimately manipulated by Kor Phaeron and Erebus, Lorgar initially started out as the most devout of the Emperors sons, bringing whole populations to worship the Emperor as a God (irony). The Emperor chastised and humiliated Lorgar for these acts and cemented the rivalry between the Ultramarines and Word Bearers as a result. In his grief, Lorgar was easily swayed to the ruinous powers in his quest for knowledge and a deity to worship. Though he was the first Primarch to fall to Chaos, I don't believe him to be inherantly evil, just weak and easily swayed. As with Magnus and Horus (and Angron to an extent), it is the Emperors actions that led him down the path to Chaos every bit as much as his own, subsequent actions.

5. Angron - when reading some stories about Angron it is easy to feel sorry for the red angel. He has lived a life of slavery alongside his fellow gladiators, only to be ripped away from them by the Emperor at the moment their rebellion reached its pique. Without Angron the other slaves died and the grief of this irrevocably changes Angron. He never forgives the Emperor for this act, even if the intent were to save his life, and the grief he feels drives him into fits of despair and rage. This in itself would be bad enough, but the butchers nails implanted in his cortex amplify the madness and pain a dozenfold, turning Angron into a crazed beast of a Primarch, both unpredictable and uncompromising. His siding with Horus clearly stems from his distrust of the Emperor, but again I would argue that circumstance and the Emperors poor judgement is more a driving force behind Angrons betrayal that any inherent evil.  

4. Konrad Curze - now I have to admit that I know the least about Curze when compared to the other Primarchs. As far as I can tell thought, Curze, although a murderous psychopath, had a pretty hard time of things. He wasn't raised with any kind of nurturing and was constantly plagued by waking dreams of the worst kind. Despite growing up as a kind of vigilante on Nostromo, his ways soon led to all out terror and murder. He wasn't close to any of his other brothers and so when Nostromo rebelled he reacted in the only way he knew and destroyed it utterly. He is in ways very similar to Angron in that he has had his character and decisions forced upon him rather than choosing it willingly. Despite this he is a psychotic despot and thus has earned a place below some but not all Primarchs in the list.  

3. Horus - it was a toss-up as to whether Horus would make it into the top 3, but then again is is the HORUS heresy after all. Horus was more of the architect of his own downfall. Being supremely ambitious like his father was always going to lead to problems one day. After all, there's only room for one at the top. There's a bit more to it than that though. Horus felt betrayed by his father big time. Being the closest to the big E, Horus felt betrayed at being left to fight the crusade while the Emperor returned to Terra. Despite his ambition, Horus also felt unable to bear the weight of responsibility of the crusade. When the forces of Chaos showed the (ironically accurate) future of mankind worshipping the Emperor as a God and half of the Primarchs alongside him, Horus' dejection and jealousy shifted into overdrive. Overall, his ego was his downfall, but again had the Emperor in his infinite wisdom done things just a little differently it's possible the ego could have been held in check and the heresy averted.  Still, at the end of the day he was the instigator of the Heresy.

2. Mortarion - this is another Primarch I know little about. His final defection to Nurgle may have been an act of desperation once the blight took hold, but his initial defection and outward hostility towards both other Primarchs (Magnus) makes him a pretty bad chap IMO. Besides, who else drinks poison for fun!? It seems that as soon as mention of heresy was made, Mortarion and the Death Guard were quick to join. Although the background I have read is sketchy at best, it seems there are as few redeeming features to Mortarion as there are condemning ones. Compared to his brother primarchs mentioned above, there seems little extraneous force driving his betrayal, and therefore I conclude that he was inherently a treacherous type from the start.

1. Fulgrim - the number one spot is reserved for the pretty boy who seems to have few redeeming features. Vain and arrogant in the extreme, Fulgrim was very quick to turn both to Horus and Chaos. The guy even depossessed himself of a chaos daemon because it wasn't evil enough. He tried to murder his brother Perturabo for his own gain and was the first to kill a brother Primarch, decapitating his once beloved brother Primarch, Ferrus Manus. There was no doubt in my mind when I started writing this article as to who the number one would be and it's Fulgrim every time. Anyone who wants to know why should read both Fulgrim and Angel Exterminatus.

Well it's been fun writing this one. Anyone who disagrees please get the debate going as I dare say there are elements I haven't taken into account. Cheers and hope it's been a decent read.